Thanks for posting the link to the new ASTM standard, Richard. We will need to keep track of this as it develops.
Just as an fyi, the manufacturer of the gypsum board for the courthouse we are working on indicates the following in its follow up letter regarding our project.
Quoted from the letter: “Leading scientific engineering firms have found elemental sulfur is the marker for defective Chinese wallboard and the problems some of it creates. A third-party engineering firm has tested a number of samples of our wallboard and found no detectible levels of elemental sulfur in the samples. These test results have been confirmed by other scientists”.
I’m not a chemist, but to me the difference seems to be the “elemental sulfur” in the above quote is the bad stuff, and the sulfur that is part of the compound calcium sulfate is the okay stuff.
I was just considering that same question. How about “Provide gypsum board manufactured by a member of GA.”? According to their recent position paper, their mfr’s are free of this problem.
We don’t really know that it’s elemental sulfur, do we? And how much elemental sulfur–or the problem compound of it–is normally in mined and flue-gas desulfurization gypsum? Zero is a very small number. I’d really like to see the gypsum manufacturers tackle this in a meaningful way.
We have been asked by clients to addressed this issues in specs. It has always been our practice to list manufacturers, which has at least kept us with domestic suppliers. The ASTM C 1396 standard for gypsum board does not address the “purity” of the gypsum core, so we really can’t rely entirely on that. Perhaps a bit vague - but some of the issues raised by this forum have not been addressed to my complete satisfaction - I’ve added the following in the “Quality Assurance” article.
“A. Source Limitations: Provide products manufactured within the United States from materials free of sulfur, formaldehyde or other deleterious chemicals. Natural gypsum ore shall be mined in North America. Synthetic (Byproduct) gypsum shall be pure calcium sulfate from domestic sources.”